1. Field
The present invention relates generally to a cooling fin and a package substrate comprising the cooling fin and a manufacturing method thereof, and, more particularly, to a cooling fin, which is excellent in cooling performance and is simply manufactured, a package substrate comprising the cooling fin, and a manufacturing method thereof
2. Description of the Related Art
These days, in response to miniaturization and the widening of the functionality of electronic products, more passive/active devices and semiconductor chips (IC) are mounted in the electronic products and packaged. However, as the number of their mounting and packaging are increased, power consumption and heat generation are increased, thus exerting a bad influence on reliability of products and on their attractiveness to customers.
Accordingly, in order to solve the above problems caused by the heat generation, a variety of research on cooling fins is being conducted. Recently, intensive research is being concentrated on a cooling fin incorporating carbon nanotubes (CNT) which have excellent thermal conductivity, i.e., a thermal conductivity ten times or greater than that of copper.
A carbon nanotube is typically produced through chemical vapor deposition (CVD). FIG. 1 shows a carbon nanotube 13, which is produced through chemical vapor deposition.
Referring to FIG. 1, conventional carbon nanotubes 13 are produced in a manner such that nano-sized catalytic metal particles 12 are formed on a silicon substrate 11 and then the carbon nanotubes 13 grow vertically from the catalytic metal particles through a high temperature synthesis process conducted at a temperature ranging from 500° C. to 1000° C. The carbon nanotubes 13 which have been produced in such a manner are attached to a target object so as to serve as cooling fins.
If chemical vapor deposition is used, although it is possible to grow the carbon nanotubes in a vertical direction, it is impossible to enable the carbon nanotubes to have various structures. Thus, there is a limit to the production of cooling fins whose high cooling performance is due to an increase in the surface area of the cooling fins.
Further, since the chemical vapor deposition process must be conducted at a relatively high temperature ranging from 500° C. to 1000° C., the base material from which the carbon nanotubes can be grown is disadvantageously restricted to ones which can be used at the high temperature, for example, the silicon substrate 11, as illustrated in FIG. 1.
Furthermore, the conventional process is disadvantageous in that there are needs for a separate metal catalyst 12 adapted to grow the carbon nanotube as well as a special container having a high hermetic performance regarding forming a nano-sized metal catalyst 12 on the silicon substrate 11, thus increasing equipment costs.